An Esri grid is a raster GIS file format developed by

Esri Esri (; Environmental Systems Research Institute) is an American multinational geographic information system (GIS) software company. It is best known for its ArcGIS products. With a 43% market share, Esri is the world's leading supplier of GIS ...

, which has two formats: #A proprietary

binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that ta ...

format, also known as an ''ARC/INFO GRID'', ''ARC GRID'' and ''many'' other variations #A non-proprietary

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...

format, also known as an ''ARC/INFO ASCII GRID'' The formats were introduced for ARC/INFO. The binary format is widely used within Esri programs, such as

ArcGIS ArcGIS is a family of client, server and online geographic information system (GIS) software developed and maintained by Esri. ArcGIS was first released in 1999 and originally was released as ARC/INFO, a command line based GIS system for mani ...

, while the ASCII format is used as an exchange, or export format, due to the simple and portable

file structure. The grid defines geographic space as an array of equally sized

square In Euclidean geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, π/2 radian angles, or right angles). It can also be defined as a rectangle with two equal-length a ...

grid points arranged in rows and columns. Each grid point stores a numeric value that represents a geographic attribute (such as

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § ...

or surface slope) for that unit of space. Each grid cell is referenced by its x,y coordinate location.

File formats

ASCII

In Esri grid data, the first six lines indicate the reference of the grid, followed by the values listed in "English reading order" (left-right and top-down). For example, consider a grid, shown to the left. This could be encoded into an ASCII grid file, that would look like: where *''ncols'' and ''nrows'' are the numbers of columns and rows, respectively (represented as

integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign ( −1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language ...

s); *''xllcorner'' and ''yllcorner'' are the western (left) ''x''-

coordinate In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is si ...

and southern (bottom) ''y''-coordinates, such as

easting and northing A projected coordinate system, also known as a projected coordinate reference system, a planar coordinate system, or grid reference system, is a type of spatial reference system that represents locations on the Earth using cartesian coordin ...

(represented as

real number In mathematics, a real number is a number that can be used to measurement, measure a ''continuous'' one-dimensional quantity such as a distance, time, duration or temperature. Here, ''continuous'' means that values can have arbitrarily small var ...

s with an optional decimal point), **when the data points are cell-centered ''xllcenter'' and ''yllcenter'' are used to indicate such registration. *''cellsize'' is the

length Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the Inte ...

of one side of a square cell (a real number); and, *''nodata_value'' is the value that is regarded as "missing" or "not applicable"; this line is optional, but highly recommended as some programs expect this line to be declared (a real number). The remainder of the file lists the raster values for each cell, starting at the upper-left corner. These

s (with optional decimal point, if needed) are delimited using a single

space character In computer programming, whitespace is any character or series of characters that represent horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visible mark, but typically does occupy an area ...

Binary format

A binary Esri grid is stored in several files contained in at least two directories: the ''name'' directory and an ''info'' directory, where ''name'' has strict naming conventions. The grid name must begin with an alphabetic character and must only include alphanumeric characters or the underscore ("_") character. A multiple-band grid (a collection of grids also known as a "stack" in ArcGIS) cannot have more than 9 characters in its file name, and a single-band raster dataset cannot have more than 13 characters.

References

{{reflist ;Binary grid
Arc/INFO GRID file structure
for

GDAL The Geospatial Data Abstraction Library (GDAL) is a computer software library for reading and writing raster and vector geospatial data formats (e.g. shapefile), and is released under the permissive X/MIT style free software license by the O ...

;ASCII grid
ASCII grid format
for

GIS raster file formats